It has been of high interest in the field of photography to improve image quality. It is known that image sharpness can be improved by incorporating a mordant and a dye into light-sensitive materials to thereby prevent irradiation and halation.
Use of the dye, however, is attended by the problem that the dye is not sufficiently removed during processing to cause residual color.
Residual color may be prevented by combining a dye with a mordant having weak mordanting capability, but such an approach has the disadvantage that the dye undergoes diffusion during coating, resulting in reduction of sensitivity.
On the other hand, developments in light-sensitive materials and processing agents have contributed to a considerable reduction in development time. It is usually desired, whether for professionals or amateurs, to see the finished photographs as soon as possible. In the field of printing, particularly for those in informational media, it is eagerly demanded to reduce the processing time of light-sensitive materials in order to give information quickly. Reduction of processing time is also very important in the field of medical photography, since diagnosis and treatment should be done without delay in case of emergency.
Reduction in processing time is realized by shortening the time for each of a series of processing steps including development, fixation, washing, and drying. For example, it is generally known that development time can be reduced by a method of heightening activity of a developer, e.g., by increasing the amount of a development agent or elevating the pH or the processing temperature; or by a method of accelerating the rate of development of a silver halide emulsion per se.
The time for washing or drying greatly depends on the thickness and degree of swelling of a coated film. The time may be shortened by using, as a binder, gelatin whose crosslinkability has been increased by addition of a sufficient amount of a hardening agent. However, this method reduces the covering power of the silver halide, thus requiring an increase in silver coverage, or results in reduction of sensitivity, delay of development, and reduction of the rate of fixation. To increase the amount of the binder, therefore, leads to considerable difficulties in rapid processing.
In direct radiography for medical use, for the purpose of decreasing the exposed dose of X-rays harmful to the human body, X-ray films generally have a support having an emulsion layer provided on both sides thereof, and a radiographic intensifying screen is set on both surfaces of the film to obtain a considerable degree of intensification. A disadvantage associated with this radiographic system is called a "cross-over phenomenon". That is, the light emitted from each of the intensifying screens is not only projected onto the respective silver halide emulsion layer which is in contact with the screen but also transmitted through the emulsion layer and the support to become scattered light which reaches the emulsion layer on the opposite side to form an image having low sharpness. In an attempt to overcome the cross-over phenomenon, it has been proposed to add a magenta dye or a yellow dye to an orthochromatic light-sensitive material to improve sharpness as disclosed in U.S. Pat. No. 4,130,429 and JP-A-61-116354 and JP-A-61-116349 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application"). However, mere addition of a dye to a silver halide emulsion layer inevitably results in considerable photographic desensitization due to its optical absorption. Hence, such a dye is added to an interlayer provided between the silver halide emulsion layer and the support. Nevertheless, formation of such an interlayer causes diffusion of the dye on coating of the emulsion layer, which leads to more or less photographic desensitization. To make matters worse, provision of an interlayer requires gelatin or any other binder in significant quantities, and drying properties of the light-sensitive material are deteriorated due to the increase of the binder amount, thus reducing suitability for rapid processing.
In order to cope with the above-described problems, JP-A-62-70830 and JP-A-55-33172 disclose techniques in which a water-soluble dye which can be decolored during photographic processing is fixed in a subbing layer provided on a support by use of a basic high polymeric mordant. Although these techniques are very effective, it has conventionally been difficult to sufficiently fix the water-soluble dye in a gelatin layer, since the gelatin content of a subbing layer is generally as small as 0.5 g/m.sup.2 or even less.